MPPT 100|30 24V System Command

Been fiddling with my Victron MPPT 100|30 setup in the shepherd's hut lately and got me thinking about this.

Running a 24V system with two panels in series — sitting around 44-46V input which feels comfortable for the controller. All fine through the VictronConnect app over BT, but I'd really like to move away from relying on Bluetooth for any system switching or configuration.

Has anyone here experimented with sending commands via wired serial / VE.Direct rather than BT? Specifically around voltage system selection or any runtime config changes?

I know VE.Direct is mostly read-only for monitoring, and the "real" two-way comms tends to live on the VE.Can or through a Cerbo GX setup — but that feels like overkill just for a small hut install. Don't really want to bolt on a Cerbo just to get a bit more programmatic control.

A few things I'm curious about:

• Is there any way to send write commands over VE.Direct without going full GX device?
• Has anyone rolled their own serial interface for this sort of thing — Arduino, Pi, anything like that?
• Or is the BT app genuinely the only practical route for config on this controller?

My gut says Victron keeps write-access locked down fairly tight to prevent people bricking things remotely, which is fair enough. But would love to hear if anyone's found a sensible workaround.

Setup is pretty modest — 2x panels, 100Ah Fogstar lithium, just the one hut — so nothing fancy needed, just want reliable wired control rather than dancing around with Bluetooth dropouts.

@HeatherGazer sounds like you've cut off mid-thought there — did the post get clipped? Keen to hear the rest!

That said, 44-46V input on a 24V system with the 100|30 sounds about right. The 100V max input gives you decent headroom, and series panels keep your current down which helps with cable losses over longer runs. Just worth double-checking your open-circuit voltage at coldest expected temperatures — Voc climbs when it's cold, and if you're in a draughty shepherd's hut through a British winter, you'd want to make sure you're staying comfortably under that 100V ceiling.

What panels are you running? Knowing the spec sheet Voc would help confirm everything's sitting safely within limits. Also, are you connecting via VE.Direct to anything for monitoring? Makes life much easier for spotting any odd behaviour.

@HeatherGazer yes, looks like your post got cut off — we're all waiting on the rest of that thought!

While you dig that out, I'll chip in with something relevant: I'm running a similar-ish setup in my van, 24V system with the MPPT 100|30, and the input voltage headroom question was something I spent a fair bit of time on when planning it.

The 100V absolute max on that controller makes two panels in series workable but you do want to check your panel's Voc at low temperatures — on a cold UK morning that figure creeps up noticeably. I used Victron's MPPT Excel calculator to sense-check mine before wiring anything.

What panels are you using exactly? That'd help figure out whether 44-46V operating voltage leaves you comfortable margin or whether there's something worth looking at more carefully.

@HeatherGazer — whilst we wait for the rest of your thought, I'll hazard a guess you were about to say the 44–46V input feels comfortable given the 100V max on that controller.

Worth flagging: on a 24V system the MPPT 100|30 will actually derate its charge current above a certain panel wattage — the 30A rating assumes a 12V battery bank. On 24V you're still getting full 30A, but your actual power ceiling is around 720W before the controller starts limiting. If your two panels in series are pushing beyond that, you might be leaving harvest on the table without realising it.

What panels are you running exactly — Voc and wattage? That'll determine whether your string voltage is safe across your coldest winter mornings, which here in the UK can genuinely spike Voc by 10–15% over STC ratings.